From: Claudio Imbrenda <imbrenda@linux.ibm.com>
To: David Hildenbrand <david@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org,
kvm@vger.kernel.org, linux-mm@kvack.org,
Christian Borntraeger <borntraeger@de.ibm.com>,
Janosch Frank <frankja@linux.ibm.com>,
Cornelia Huck <cohuck@redhat.com>,
Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Niklas Schnelle <schnelle@linux.ibm.com>,
Gerald Schaefer <gerald.schaefer@linux.ibm.com>,
Ulrich Weigand <Ulrich.Weigand@de.ibm.com>
Subject: Re: [PATCH resend RFC 8/9] s390/mm: optimize set_guest_storage_key()
Date: Mon, 27 Sep 2021 19:01:57 +0200 [thread overview]
Message-ID: <20210927190157.65ce9f54@p-imbrenda> (raw)
In-Reply-To: <20210909162248.14969-9-david@redhat.com>
On Thu, 9 Sep 2021 18:22:47 +0200
David Hildenbrand <david@redhat.com> wrote:
> We already optimize get_guest_storage_key() to assume that if we don't have
> a PTE table and don't have a huge page mapped that the storage key is 0.
>
> Similarly, optimize set_guest_storage_key() to simply do nothing in case
> the key to set is 0.
>
> Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> ---
> arch/s390/mm/pgtable.c | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
> index 4e77b8ebdcc5..534939a3eca5 100644
> --- a/arch/s390/mm/pgtable.c
> +++ b/arch/s390/mm/pgtable.c
> @@ -792,13 +792,23 @@ int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
> pmd_t *pmdp;
> pte_t *ptep;
>
> - if (pmd_lookup(mm, addr, &pmdp))
> + /*
> + * If we don't have a PTE table and if there is no huge page mapped,
> + * we can ignore attempts to set the key to 0, because it already is 0.
> + */
> + switch (pmd_lookup(mm, addr, &pmdp)) {
> + case -ENOENT:
> + return key ? -EFAULT : 0;
> + case 0:
> + break;
> + default:
> return -EFAULT;
> + }
>
> ptl = pmd_lock(mm, pmdp);
> if (!pmd_present(*pmdp)) {
> spin_unlock(ptl);
> - return -EFAULT;
> + return key ? -EFAULT : 0;
> }
>
> if (pmd_large(*pmdp)) {
next prev parent reply other threads:[~2021-09-27 17:09 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-09 16:22 [PATCH resend RFC 0/9] s390: fixes, cleanups and optimizations for page table walkers David Hildenbrand
2021-09-09 16:22 ` [PATCH resend RFC 1/9] s390/gmap: validate VMA in __gmap_zap() David Hildenbrand
2021-09-14 16:53 ` Claudio Imbrenda
2021-09-09 16:22 ` [PATCH resend RFC 2/9] s390/gmap: don't unconditionally call pte_unmap_unlock() " David Hildenbrand
2021-09-14 16:52 ` Claudio Imbrenda
2021-09-09 16:22 ` [PATCH resend RFC 3/9] s390/mm: validate VMA in PGSTE manipulation functions David Hildenbrand
2021-09-14 16:54 ` Claudio Imbrenda
2021-09-09 16:22 ` [PATCH resend RFC 4/9] s390/mm: fix VMA and page table handling code in storage key handling functions David Hildenbrand
2021-09-27 16:37 ` Claudio Imbrenda
2021-09-09 16:22 ` [PATCH resend RFC 5/9] s390/uv: fully validate the VMA before calling follow_page() David Hildenbrand
2021-09-14 16:53 ` Claudio Imbrenda
2021-09-14 22:41 ` Liam Howlett
2021-09-09 16:22 ` [PATCH resend RFC 6/9] s390/pci_mmio: fully validate the VMA before calling follow_pte() David Hildenbrand
2021-09-14 16:54 ` Claudio Imbrenda
2021-09-14 22:41 ` Liam Howlett
2021-09-09 16:22 ` [PATCH resend RFC 7/9] s390/mm: no need for pte_alloc_map_lock() if we know the pmd is present David Hildenbrand
2021-09-14 16:54 ` Claudio Imbrenda
2021-09-14 17:23 ` David Hildenbrand
2021-09-09 16:22 ` [PATCH resend RFC 8/9] s390/mm: optimize set_guest_storage_key() David Hildenbrand
2021-09-27 17:01 ` Claudio Imbrenda [this message]
2021-09-09 16:22 ` [PATCH resend RFC 9/9] s390/mm: optimize reset_guest_reference_bit() David Hildenbrand
2021-09-27 17:02 ` Claudio Imbrenda
2021-09-14 16:50 ` [PATCH resend RFC 0/9] s390: fixes, cleanups and optimizations for page table walkers Claudio Imbrenda
2021-09-14 18:06 ` David Hildenbrand
2021-09-28 10:59 ` Heiko Carstens
2021-09-28 11:06 ` Christian Borntraeger
2021-09-28 14:38 ` Claudio Imbrenda
2021-09-28 16:03 ` Christian Borntraeger
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210927190157.65ce9f54@p-imbrenda \
--to=imbrenda@linux.ibm.com \
--cc=Ulrich.Weigand@de.ibm.com \
--cc=borntraeger@de.ibm.com \
--cc=cohuck@redhat.com \
--cc=david@redhat.com \
--cc=frankja@linux.ibm.com \
--cc=gerald.schaefer@linux.ibm.com \
--cc=gor@linux.ibm.com \
--cc=hca@linux.ibm.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-s390@vger.kernel.org \
--cc=schnelle@linux.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).